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MIT Wheelchair/Bed Aims to Boost Independence

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CAMBRIDGE, Mass-MIT researchers have developed a wheelchair with uniqueresponsiveness to human muscle pressure, so tasks that previously requiredthe help of another person-in most cases, a nursing home or hospitalaide-can now be accomplished unassisted.

The wheelchair, combined with a horseshoe-shaped bed, forms asystem known as RHOMBUS (Reconfigurable Holonomic Omnidirectional MobileBed with Unified Seating). The powered wheelchair can be docked in thehorseshoe portion of the system and reconfigured to a flat, stationaryposition forming a twin-size bed. The wheelchair's speed and direction arecontrolled by operating a joystick or by giving commands to the onboardcomputer.

The RHOMBUS system allows bedridden or wheelchair-bound persons tobe in either a bed or a chair without changing seating and without havingto lift themselves or be lifted by others.

It and other health-care devices in development at MIT were demonstrated ata recent MIT Workshop on Healthcare Robotics chaired by H. Harry Asada,Ford Professor of Engineering in the Department of Mechanical Engineering.The workshop was sponsored by the National Science Foundation.

Joseph S. Spano and Stephen A. Mascaro, both graduate students inthe Department of Mechanical Engineering, developed the hybridbed/wheelchair system with Professor Asada and Masayoshi Wada of Fuji.Professor Asada is also director of the d'Arbeloff Laboratory forInformation Systems and Technology.

Mr. Spano developed the chair portion of RHOMBUS, which is equippedwith a teleconferencing facility resembling an enlarged side-view mirror ona car, so the homebound person can communicate face-to-face with a distantcaregiver, relatives and friends. Mr. Mascaro developed the vehicleportion, which is capable of omnidirectional (all-direction) motion.

To get a realistic view of how RHOMBUS might be used, Spano andMascaro visited a local nursing home.

"I'm from car country, and that looked like an engine hoist," saidMr. Spano, a California native, when he saw the mechanism and the effortinvolved in transferring a patient from a bed to a wheelchair. RHOMBUS, henoted, would take less work and provide privacy and dignity to an elderlyperson.

"Control is implicit here," Mr. Spano said. "If your mind is soundbut your body is weak, the chair will compensate." For example, slightmuscular pressure on the back of the chair will engage it mechanically tolower toward the bed. When muscle pressure stops, or "zeroes out," thechair holds its position.

Both Mr. Spano and Mr. Mascaro acknowledged the leap betweensolving the mechanical problems of RHOMBUS and making the systemuser-friendly for elderly people They see the next challenge of RHOMBUSarising from fundamental questions as to how average people will use newhealth-care technology in their own home environments.

"Older people aren't going to interface easily with a big machine,"noted Mr. Spano. For the sake of their comfort, the researchers would liketo "get around using buttons and dials."

New features planned for addition to the current RHOMBUS prototypeinclude force-guided docking control, which would allow the vehicle to beprecisely "mated" with fixtures. This would include connecting a battery toa battery charger, liquid containers to pipes, and the vehicle itself to atoilet.

Funding for the patent-pending RHOMBUS has been provided by aconsortium of industrial sponsors.

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